In a steam-using facility comprised of a steam-using equipment, in the event of failure of the steam-using equipment, repair or replacement of this steam-using equipment, moreover, stop of the operation of the steam-using facility associated with such repair or replacement is required. This entails repair cost or replacement cost, and also results in loss of profit which would be obtained originally from the operation of the steam-using facility. Thus, there will occur significant loss.
According to a conventional practice implemented to address to the problem above, the state of the steam-using equipment (e.g. a rotational speed in the case of a steam turbine) or a steam state such as a steam pressure or steam flow rate of steam coming in/out of the steam-using equipment is on-line monitored. So that, based on a change in these, abnormality in the steam-using equipment is detected before it causes a failure of the steam-using equipment, whereby development of the problem to failure of the steam-using equipment is inhibited.